The cellular biology of the human trabecular meshwork will be studied to gain insights into the pathogenesis and treatment of glaucoma. Studies will continue to use the perfusion organ culture system of the trabecular meshwork developed previously. This system allows trabecular cells to remain in situ on the trabecular lamellae, and receive the flow of culture medium in physiologic fashion as the fluid flows through the meshwork before entering Schlemm's canal. The long-standing theory of altered phagocytic capacity in glaucomatous eyes and in steroid treated eyes will be examined. The anterior chamber of cultured eyes will be infused with fluorescent microspheres which have been labeled with IgG. After application of a secondary antibody tagged with a contrasting fluorescent dye, the meshwork will be analyzed with fluorescence microscopy. A computerized image analysis system has been programmed to quantitate the amount and color of each fluorescent dye (microspheres: FITC; secondary antibody: rhodamine). This will allow the rapid quantitation of the phagocytotic activity of the trabecular cells, and also allow distinguishing ingested from adsorbed microspheres. The mechanism of the improved outflow facility produced by epinephrine, cytochalasin, and ethacrynic acid will be examined. A rapid method for quantitative analysis of the various tissue components and empty spaces of the juxtacanalicular tissue will be used to examine this tissue before (via trabeculectomy specimens) and after infusion of the drugs. Several statistical questions will be addressed first: the variability of this tissue between histologic sections, the variability around the circumference of the eye, and the variability caused by the two commonly used fixation techniques, immersion or perfusion of fixative through the meshwork.